Clip actuated latch mechanism for retractable writing instruments

Abstract

Mechanism for putting the head of a shaft into and out of the head of an outer sleeve comprised of an outer sleeve (1), a long hole (2) formed in the outer sleeve (1), and a clip (3) to be put into and out of the outer sleeve (1) through the long hole (2). A shaft (4) is inserted in the outer sleeve (1), and a cam mechanism (8) cooperates with the clip (3) in a manner that causes the cam mechanism (8) to move forward and backward in an axial direction according to in and out movement of the clip (3). A spring (6) spring-biases the shaft (4) toward the cam mechanism.

I claim: 
     
       1. Mechanism for extending and retracting the head of a shaft through the head end of an outer sleeve, comprising; an outer sleeve (1), a long hole (2) formed in said outer sleeve (1), a clip (3) adapted to be moved in and out of said outer sleeve (1) through said long hole (2); a writing shaft (4) inserted in said outer sleeve (1); a cam mechanism (8) having front and rear slopes (12,14), actuating means (9,10a) integrally formed on said clip (3) engaging said front and rear slopes (12,14); a socket in said cam mechanism (8) receiving an end of said writing shaft (4); a spring (6) holding said writing shaft (4) in said socket; a retaining shoulder (13) at an inner end of said front slope for receiving and retaining said front actuating means (10a); a fulcrum member (16) at an inner end of said rear slope for receiving said rear actuating means (9); whereby downward pressure on a forward portion of said clip (3) moves said cam mechanism (8) and writing shaft (4) axially forward extending the head end (7) with said front actuating means (10a) being engaged in and retained by said retaining shoulder (13) and downward pressure on a rear portion of said clip (3) causes said rear actuating means (9) to engage said fulcrum member (16) releasing said front actuating means (10a) from said retaining shoulder (13) allowing said cam mechanism and said writing shaft to retract. 
     
     
       2. The mechanism according to claim 1 in which said fulcrum member comprises an upward curving projection (16) at the end of said rear slope (14) so that said rear actuating means (9) rides up said curved projection (16) when pressure is applied to a rear portion of said clip (6) dislodging said from actuating means (10a) from said retaining shoulder (13). 
     
     
       3. The mechanism according to claim 1 in which said rear actuating mechanism (9) is formed by a lengthwise hole in said clip (3) receiving said rear slope (14). 
     
     
       4. The mechanism according to claim 1 in which said front actuating means (10a) comprises a retaining portion formed on said clip for retaining said clip in said long hole (2) in said sleeve (1).